Pavement

The Everyday Miracle

You'll never ignore that ordinary strip of pavement under your wheels again

lisa margonelli

(Photo by C.J. Burton)

Chapter 1: My obsession with asphalt was born on a bike ride through a cemetery

I don't remember how I ended up there that day. Maybe I pedaled up for the view, a smashing panorama of the San Francisco skyline that lies at the end of a grand network of roads and paved lanes that reach up into the hills. Or maybe I was delaying the end of a too-short ride by tacking on a detour that meandered among prim headstones and Munsteresque family crypts. What I do remember clearly is sensory—sniffing the freshly cut grass near the entrance, then noticing the sound of my tires on the pavement, something like sizzling bacon. As I started riding uphill, the smooth, black, buttery layer of asphalt gave way to something crunchy, like the crumb topping on a coffee cake. Little cascades of stones skittered away from my tires. The pavement changed again, tight and brownish. Cracks appeared, then a puzzling, fresh patch of pitch-black asphalt. There came a pothole. And, just past a grave labeled Nutter, the pavement gave up entirely, and the road turned to dirt.

All the major existential questions rushed at me: Why does some asphalt stay and some asphalt go? Where do roads come from? What was that sizzling sound? When I was four, a paving crew appeared one summer day in front of our house. My mom, who enjoyed fermenting sauerkraut at home, warned me to stay far away from the commotion. I spent the day watching the birth of a road from behind a shrub. Asphalt was black and shiny, steaming hot, apparently somewhat gooey, and it reeked of decayed dinosaur. Irresistible. No sooner had the crew departed for the day than I took off my shoes and ran toward the road, hoping to leave an impression of my feet. I jumped onto the blacktop—and had a Wile E. Coyote moment, becoming a cartoon child frozen in midair, puffs of black smoke tooting from my feet, eyes like fried eggs, legs pleated like accordions, etc.

Back at the curb, I was disappointed to see that I'd left no impression on the blacktop whatsoever. Worse, the new road had left its mark on me—clots of gunky black tar clung to the ball of each toe. The clots would not come off. I was marked. Ten toes carried the black spot—proof that I'd not only "gone near the asphalt," but also committed the spanking-worthy crime of "playing in the road." My heart pounded. Punishment was nigh. Then a deception occurred to me: socks. I put on socks and kept them on for days.

And so, asphalt became my first furtive pleasure.

Under the cumulative strain of later furtive pleasures—none appropriate for a cycling magazine—asphalt had faded from my consciousness. Like anyone who rides a bicycle, I was aware of its effect on me from time to time. But there in the cemetery, it struck me that despite all the effort cyclists put into understanding how to ride—how to train and handle a bike, eat properly and perform maintenance—and despite the appreciation we lavish on smooth roads and the disdain we heap upon broken pavement, we know almost nothing about the surface on which our wheels spin. Maybe it's just as well, because once I started really thinking about the literal foundation of our sport, it was easier to keep going than to stop.

Chapter 2: Our bikes are designed to isolate us from pavement

We feel the road through vibration-absorbing frames and gel saddles and shock-absorbing seatposts and thick, padded handlebar tape. The only time we really experience asphalt is when our tires stop grabbing it, and we fall.

That moment seemed as good a place as any to begin. It turned out that the man who understood why bike tires fall prey to what people who study such things call slip out was Jobst Brandt, an engineer and author of The Bicycle Wheel, the seminal work on the subject. Brandt informed me that the interaction of tire and pavement fell under the subject of tribology—the study of friction, lubrication and wear.